The invention relates to improvements in valves of the type disclosed in commonly owned U.S. Pat. No. 4,739,929 granted Apr. 26, 1988 to Brandner et al., and in commonly owned published German patent application No. 35 32 660 of Brandner et al. More particularly, the invention relates to improvements in piezoceramic means for moving the valving elements in fuel injection valves and/or other types of valves in response to energization of their flexural resonators.
The published German patent application of Brandner et al. discloses a valve wherein the piezoceramic moving unit comprises a plurality of flexural resonators all of which are flexed in the same direction in response to energization so that they can move the valving element with a relatively large force. However, the distance which is covered by the valving element in response to energization of the resonators is rather short.
Published German patent application No. 24 02 085 discloses a valve moving unit which relies upon longitudinal resonators. Thus, the distances which are covered by individual resonators are totalized in response to energization to thus ensure that the valving element is moved through a greater distance. Neighboring resonators abut each other in energized and deenergized condition.